盾构隧道平行穿越连拱隧道施工影响分析及安全控制研究

发布时间：2018-04-24 18:13

本文选题：盾构隧道 + 穿越施工　；参考：《长安大学》2017年硕士论文

【摘要】：近年来我国掀起了城市地铁盾构隧道建设的热潮,盾构隧道近接施工越来越普遍。但是,新建盾构隧道与既有连拱隧道近距离平行穿越的复杂形式尚不多见,施工时既有连拱隧道的结构安全可能会受到影响,对于城市地铁而言是一种挑战,需要合理处理。为此,本文以西安地铁4号线航天新城~航天东路区间隧道工程实例为依托,分别从理论分析、数值模拟、现场实测方面分析盾构隧道穿越既有连拱隧道的影响规律及穿越施工期间采取的施工工程措施。论文的主要研究工作如下:(1)根据弹性力学Mindlin解得到了盾构施工正面推力和侧壁摩擦力引起的土体变形及附加应力计算公式,同时结合镜像法基本原理对土体损失引起的附加应力进行了求解,得到三者共同作用下总的附加应力计算公式。利用MATLAB对依托工程中连拱隧道轴线位置处土体位移及作用于连拱隧道上的附加荷载分布情况进行了系统的分析计算。(2)建立新建盾构隧道穿越既有连拱隧道的三维数值计算模型,利用空模型、改变单元材料参数和施加面力等方法实现土体开挖、支护压力施加、注浆压力施加、管片拼装等动态施工过程的精细化模拟,分析盾构隧道在施工过程中对连拱隧道支护结构及周边围岩的影响规律。(3)以不同围岩软硬程度、隧道净距、注浆压力及土仓压力这四个主要参数进行了参数变化分析。(4)分析、总结了国内外相关标准和和类似工程经验,初步制定了盾构隧道穿越连拱隧道安全施工控制标准,以确保既有连拱隧道结构安全。详细介绍了盾构穿越施工时的参数计算及选取,通过与现场第350环~707环施工时土仓压力、掘进速度、同步注浆压力、推力、出土量、刀盘扭矩及转速的统计数据比较表明:计算所得参数与所采用的掘进参数较为吻合。并对盾构隧道近距离平行穿越连拱隧道施工时的土体加固措施、连拱隧道结构加固措施进行简要介绍、分析,为类似穿越工程提供安全控制措施方面的建议。(5)对穿越施工现场监测项目、断面及测点布置、监测元件及监测结果等进行简要介绍。结合隧道施工对地表建筑(构)筑物的影响、日本隧道近接施工指南,根据盾构隧道施工前后连拱隧道拱顶竖向位移、二次衬砌混凝土压应力变化提出了基于位移准则及强度准则的影响分区方法,针对盾构施工对新建连拱隧道结构影响可进行有效分区。现场施工过程中盾构隧道最终安全通过穿越段,且既有连拱隧道的衬砌结构未出现裂缝,表明现场采用的施工方案及措施是合理的,可以切实地解决施工所面临的问题,对今后相似穿越形式的城市地铁隧道建设具有一定的借鉴作用。
[Abstract]:In recent years, the urban subway shield tunnel construction upsurge in China, shield tunnel construction is becoming more and more common. However, the complex forms of parallel crossing between the newly built shield tunnel and the existing multi-arch tunnel are rare, and the structural safety of the existing double-arch tunnel may be affected during the construction, which is a challenge to the urban subway and needs to be dealt with reasonably. For this reason, based on the practical example of the tunnel project between the space new city and the east space road of Xi'an Metro Line 4, this paper analyzes and simulates the tunnel from the theory and the numerical simulation, respectively. The influence of shield tunneling through the existing multi-arch tunnel and the construction measures taken during the construction are analyzed. The main research work of this paper is as follows: (1) according to the Mindlin solution of elastic mechanics, the formulas of soil deformation and additional stress caused by the front thrust and friction force on the side wall of shield tunneling are obtained. At the same time, combined with the basic principle of mirror image method, the additional stress caused by soil loss is solved, and the calculation formula of total additional stress under the joint action of the three methods is obtained. In this paper, the displacement of soil at the axis of multi-arch tunnel and the distribution of additional load acting on multi-arch tunnel are systematically analyzed and calculated by using MATLAB). The three-dimensional numerical calculation model of newly built shield tunnel passing through the existing multi-arch tunnel is established. The dynamic construction process such as soil excavation, support pressure, grouting pressure, segment assembly and so on are simulated by means of void model, changing the material parameters of the unit and applying the surface force, etc. This paper analyzes the influence law of shield tunnel on the supporting structure of multi-arch tunnel and surrounding surrounding rock during the construction process. It analyzes the four main parameters, including soft and hard degree of surrounding rock, net distance of tunnel, grouting pressure and pressure of soil storehouse. This paper summarizes the relevant standards and similar engineering experiences at home and abroad and preliminarily formulates the safety construction control standard of shield tunneling through multi-arch tunnel in order to ensure the structural safety of existing multi-arch tunnel. The calculation and selection of parameters during shield tunneling construction are introduced in detail. The earth chamber pressure, tunneling speed, synchronous grouting pressure, thrust force, unearthed amount are obtained through the construction of No. 350 ring and 707 ring on the spot. The comparison of the torque and rotational speed of the cutter head shows that the calculated parameters are in good agreement with the tunneling parameters. The reinforcement measures of soil mass and the reinforcement measures of multi-arch tunnel structure during the construction of shield tunnel through parallel arch tunnel are briefly introduced and analyzed. The suggestion of providing safety control measures for similar crossing projects is a brief introduction to the site monitoring items, section and point arrangement, monitoring elements and monitoring results of crossing construction. Combined with the influence of tunnel construction on surface building (construction), according to the vertical displacement of arch roof of multi-arch tunnel before and after shield tunnel construction, the Japanese tunnel construction guide is used. The influence zoning method based on displacement criterion and strength criterion is put forward for the change of compressive stress of secondary lining concrete, which can be effectively partitioned in view of the influence of shield construction on the structure of new multi-arch tunnel. In the course of field construction, shield tunnel passes through the passage section safely, and there is no crack in the lining structure of the existing multi-arch tunnel, which indicates that the construction plan and measures adopted on the spot are reasonable and can solve the problems faced by the construction. It can be used for reference in the construction of similar subway tunnel in the future.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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